What rpm motor for a South Bend 13"?

[oddball racing]

South Bend 13" step pulley (about c.1953) The title says it all, I realise that the hp ratings can vary depending on how hard that lathe would actually work, but to get proper speeds for proper machining how fast does the drive motor's output speed need to be.
Thanks, Mike

[quadrod]

some of the 13's came with a three step pulley and a single speed 1750 rpm motor and some came with a four step pulley ( cone pulleys ) and two speed motor, 1750 and 680? on my 13 i have the two speed motor but only have the high speed windings powered up as i use a VFD to drive the 3ph motor. it is a two horse power motor and with a 11 grove serpentine belt you can use all two horse power.
in other words, you need a two horse, 1750 rpm motor, single phase or three phase your choice... although with a three phase motor and a VFD you can have any spindle speed you want with very few belt changes with a twist of a knob.

[Ohio Mike]

My catalog shows that in the late 50s you could order a 13" with either a 1 HP or 1.5 HP single speed or a 1.5 HP two speed motor.

[BigBoy1]

My 13" SB

My SB 13" left the factory in 1948 and is a four pulley model. I have every reason to suspect the motor in it, is the original one. The motor is a 3 phase 1HP with a single speed of 1710 rpm (Plate info.)